Air director for furnaces



June 5, 1962 c. w. USCHOLD 3,037,550

AIR DIRECTOR FOR FURNACES Filed Jan. 27, 1960 2 Sheets-Sheet} INVENTOR. I6 I! c'mymczs W Uscnow,

June 5, 1962 C. W. USCHOLD AIR DIRECTOR FOR FURNACES 2 Sheets-Sheet 2 Filed Jan. 2'7, 1960 jw i INVENTOR. myavcs W USU-10L];

firm/ m fates This invention relates to oil burners and, more particularly, to a combustion air intake assembly adapted to be secured in operative association with an opening in the wall of a fire box of a fuel oil burner heating plant.

The eflicient and economical operation of fuel oil burners is substantially dependent upon the proper supply of combustion air to the fire box. An object of this invention therefore, is to provide an adjustable air intake housing for fuel oil burner heating plants that is simple in construction, elficient in operation, and which is adapted to uniformly and evenly control the supply of air thereto.

Another object of this invention is to provide an adjustable air intake housing that is adapted to develop maximum heat Within the fire boxes of domestic, commercial, and industrial heating plants using liquid, gas, or pulverized fuels.

All of the foregoing and still further objects and advantages of this invention will become apparent from a study of the following specification, taken in connection with the accompanying drawing, wherein:

FIGURE 1 is a perspective view of an adjustable air intake housing made in accordance with the present invention, in operative association with a fuel oil fired heating plant;

FIGURE 2 is a side elevational view of the device shown in FIGURE 1, with parts broken away and partly in section, showing the construction of the air intake housing;

FIGURE 3 is a cross sectional view taken along line 3-3 of FIGURE 2; and

FIGURE 4 is a cross sectional view taken along line 4-4 of FIGURE 2.

Referring now to FIGURE 1 of the drawing, an air intake housing 14 made in accordance with the present invention is shown in operative association with the fire box of a fuel oil fired heating plant. The fire box is enclosed by fire brick 12 and is directly beneath the boiler 13 that is substantially coextensive therewith, as more clearly shown in FIGURE 2.

The air intake housing 14 includes an inner attaching plate 15a having an opening 33 therethrough of the same diameter as the opening 32 through the front wall 30 of the fire box ill). The housing 14 further includes an outer plate 16 having an inwardly extending peripheral skirt 17 around the top and the two sides of the housing, the inner edge of the skirt being provided with an external flange 15 secured to the plate 15a beyond the border of the opening 33. At the bottom of the housing 14 the skirt 17 has a damper opening 18 in which a damper 40 is pivoted on horizontal hinges 43 and is adapted to be manipulated by a handle 45. The specific structure of the damper and its handle are not relevant to the invention as such dampers are conventional. The outer plate 16 has a central opening 19 aligned with the opening 33, through which the cone 20 of an oil burner unit 21, secured by a mounting plate 23 to the outside of the plate 16, extends. A truncated air deflector cone 24 of greater length and larger radial dimensions than the cone 20 is secured to the plate 16 concentric with the cone 20 by means of a flange 25 extending radially from the base of the cone 24. A verically movable adjustment plate 27' is slidably mounted against the plate 150 and is provided with a pair of laterally spaced vertical slots 28. Studs 29 secured to the plate 15a register in art these slots. The plate 27 has an opening 27a and an inwardly (toward the fire box) extending circumferential flange 3 1 surrounding the opening 27a and extending through the opening 33 in the plate 15a. The atomized fuel is delivered through the cone 20 of the oil burner unit 21 in the conventional manner by the fuel injection nozzle shown in broken lines at 2011 in FIG. 2.

The housing 14 which includes all of the elements just described "as well as means described below for moving the plate 27 vertically and retaining it in the selected vertical position, is adapted to be secured against the front wall 30 of the fire box in the position shown in FIG. 2, wherein the openings through the cones 2d and 24 and through the plate 15a and the fire box opening 32 are all in alignment, and with the flange 3 1 whose diameter is larger than that of the smaller end of the cone 24 and smaller than that of the opening 32, projecting into the fire box.

An adjustment bolt 35 is rotatably supported within a bracket 36 carried by the top of the skirt 17 and extends into threaded engagement with a bracket 38 carried by the adjustment plate 27. Thus, rotation of the adjustment bolt is operative to regulate the vertical position of the adjustment plate with respect to the inner extremity of the air deflector cone 24 that is partially received within the circumferential flange 31. Therefore, air entering the housing through the opening 18 at the bottom end thereof is drawn through the space defined by the air deflector cone 24 and the circumferential flange 31, the quantity of air passing therebetween being directly related to the extent of vacuum created by the high velocity primary air that passes from the fan of the burner 21 through the primary air cone 20. By raising the adjustment plate 27, a larger quantity of air is caused to pass into the fire box from the upper part of the space between the deflector cone and the flange 31. Conversely, lowering the adjustment plate permits a greater quantity of air to pass between the lower end of the deflector cone and the flange 31. In this way, a proper amount of air may be distributed into the combustion chamber at the point of atomization of the fuel where the flame begins.

The handle 45 secured to the damper 40 is operative to adjust the position of the damper to enlarge or restrict the size of the opening 18 that communicates with the interior of the fire box. Thus, the damper 40 may be moved from a completely open position shown in full lines in FIG. 2 to a completely closed position shown in broken lines at 40a, as may be required. Such dampers controlling intake of secondary air are conventional.

It is well known that the quantity of air available in the fire box, which is delivered with the atomized fuel through the cone 20, amounts to only about twenty percent of the quantity required for combustion, for which reasons an additional or secondary air supply is conventionally supplied through a damper opening such as indicated at 18 which, in the instant case, is positioned at the bottom of the housing '14 below the burner. Such additional air which is sucked into the fire box is for the most part available for fuel combustion only at the lower portion of the conical path (represented diagrammatically by the arrows in FIG. 2), in the close neighborhood of the smaller end of the cone 20 In order to be effective in combustion the added air must be available very close to the smaller end of the cone; if fuel escapes a distance beyond this end into the fire box it Will be mixed very poorly with air and will burn inefliciently with consequent low heat and high carbonization of the fire box, the flue and the nozzle. Since, therefore, little of the secondary air from the damper opening meets fuel emerging from the cone 24) in the upper portions of the said path 3 shown by the arrows, the fuel in that portion is inefiiciently burned.

With the bafile plate 27 in the position shown in FIG. 2, i.e., with the axis of its opening 27a in alignment with the axis of the cones 20 and 24, the above condition of incomplete combustion remains unaltered. However, by raising the plate 27 so that the space between the lower half of the edge of the opening 27a and the smaller end of the cone 24 is decreased while proportionately increasing the space between the upper half of the opening 27a and the upper edge of the said end of the cone 24, it is obvious that a larger proportion of air sucked through the damper opening will be directed to the upper portion of the path of atomized fuel Where it emerges from the cone 20. After an installation is made the plate 27 is raised to a position which shows, by tests or experience, that a maximum of fuel consumption efiiciency has been achieved, and the plate is then left in that position. The addition of the flange 31 around the opening 27a tends to confine the secondary air which has been directed upward as just described, momentarily close to the smaller end of the cone 24 for increased efiicient utilization thereof for combustion. The vertical adjustability of the plate 27 makes it possible to attain the highest efficiency for any particular furnace set-up.

It is to be noted that the smaller end of the cone 24 is substantially in the plane of the front wall of the fire box, whereas in conventional installations the equivalent of the motor supporting plate 16 is secured directly against the front wall of the fire box so that the cone 24 projects a substantial distance into the fire box. As a consequence the instant installation permits of shortening the distance between the front and back walls of the fire box with resulting emonomy in construction costs.

It is further to be noted that while the entire unit contained, as shown, within the housing 14 is readily attachable to a conventional fire box after removal of the original burner unit, the invention as presented herein may also be embodied in newly manufactured furnaces.

While this invention has been described with particular reference to the specific form shown in the drawing, it is to be understood that such is not to be construed as imparting limitations upon the invention, which is best defined by the claims appended hereto.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. In a furnace including a fire box having a horizontal opening through a wall thereof and a burner unit mounted in alignment with said opening wherein the burner unit includes a fuel injection nozzle and a truncated air cone coaxial with and surrounding the nozzle with the smaller end of the cone pointing into the fire box and the fire box has a secondary air inlet thereinto surrounding said cone, the improvement consisting in adjustable means interposed between said opening and said cone for diverting a portion of the air passing into the fire box from said secondary air inlet from the lower portion of the smaller end of the cone to the upper portion thereof,

4. said means comprising a vertically slidable plate having an opening therelhrough of a diameter smaller than the diameter of said first-named opening and larger than the diameter of said smaller end of the cone whereby the plate is vertically movable to displace the axis of the plate opening from a given position with respect to the axis of the cone to a higher position with respect to the axis of the cone, means constraining the plate to vertical movement, and means limiting the vertical movement of the plate within a range wherein the circumferential edge of the smaller end of the cone always remains spaced from the circumferential edge of the plate opening.

2. The improvement set forth in claim 1, wherein said last-named means comprises a flange surrounding said plate opening and projecting inward with respect to the fire box beyond the plane of said first-named opening.

3. The improvement set forth in claim 1, said plate having means for raising or lowering the same.

4. In a furnace including a fire box having a vertical wall provided with a horizontal opening therethrough, a combined burner unit and adjustable secondary air supply means comprising a housing including a front wall, a top wall, side walls and a bottom wall provided with a damper-controlled opening, the housing being secured to the fire box with said walls surrounding the fire box opening, the burner unit being mounted in said front wall and having a fuel injection nozzle and a truncated air cone surrounding the nozzle positioned within the housing, a plate vertically slidably mounted in said housing adjacent said vertical wall of the fire box having an opening therethrough of larger diameter than the diameter of the smaller end of the cone and of smaller diameter than said first-named opening and normally positioned approximately in alignment with the cone and said first-named opening, means constraining the plate to vertical movement, means for varying the vertical position of the plate, and means limiting vertical movement of the plate within a range wherein the circumferential edge of said smaller end of the cone remains always spaced from the circumferential edge of the plate opening.

5. A device according to claim 4, wherein said means for varying the vertical position of said plate comprises a bracket on the upper portion of the plate having a threaded opening therein, said top wall having an opening aligned with said threaded opening, and a screw extending through said top wall opening and registering in said threaded opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,052,420 Lidstone Feb. 4, 1913 1,082,835 White Dec. 30, 1913 1,257,952 Coen Feb. 26, 1918 1,660,032 Blake Feb. 21, 1928 1,743,674 Johnson Jan. 14, 1930 1,876,962 Klahn Sept. 13, 1932 2,000,733 Avery May 7, 1935 

